ref: 567796e9236207d51b74113b75720059353063fb
dir: /src/zdither.c.unused/
/* * Highly optimised dithering 16 bits -> 8 bits. * The formulas were taken in Mesa (Bob Mercier mercier@hollywood.cinenet.net). */ #include "../include/zbuffer.h" #include <assert.h> //#include <stdio.h> #include <stdlib.h> #if defined(TGL_FEATURE_8_BITS) #define _R 5 #define _G 9 #define _B 5 #define _DX 4 #define _DY 4 #define _D (_DX * _DY) #define _MIX(r, g, b) (((g) << 6) | ((b) << 3) | (r)) #define DITHER_TABLE_SIZE (1 << 15) #define DITHER_INDEX(r, g, b) ((b) + (g)*_B + (r) * (_B * _G)) #define MAXC 256 static GLint kernel8[_DY * _DX] = { 0 * MAXC, 8 * MAXC, 2 * MAXC, 10 * MAXC, 12 * MAXC, 4 * MAXC, 14 * MAXC, 6 * MAXC, 3 * MAXC, 11 * MAXC, 1 * MAXC, 9 * MAXC, 15 * MAXC, 7 * MAXC, 13 * MAXC, 5 * MAXC, }; /* we build the color table and the lookup table */ void ZB_initDither(ZBuffer* zb, GLint nb_colors, GLubyte* color_indexes, GLint* color_table) { GLint c, r, g, b, i, index, r1, g1, b1; if (nb_colors < (_R * _G * _B)) { // tgl_fixme("zdither: not enough colors\n"); exit(1); } for (i = 0; i < nb_colors; i++) color_table[i] = 0; zb->nb_colors = nb_colors; zb->ctable = gl_malloc(nb_colors * sizeof(GLint)); for (r = 0; r < _R; r++) { for (g = 0; g < _G; g++) { for (b = 0; b < _B; b++) { r1 = (r * 255) / (_R - 1); g1 = (g * 255) / (_G - 1); b1 = (b * 255) / (_B - 1); index = DITHER_INDEX(r, g, b); c = (r1 << 16) | (g1 << 8) | b1; zb->ctable[index] = c; color_table[index] = c; } } } zb->dctable = gl_malloc(DITHER_TABLE_SIZE); for (i = 0; i < DITHER_TABLE_SIZE; i++) { r = (i >> 12) & 0x7; g = (i >> 8) & 0xF; b = (i >> 3) & 0x7; index = DITHER_INDEX(r, g, b); zb->dctable[i] = color_indexes[index]; } } void ZB_closeDither(ZBuffer* zb) { gl_free(zb->ctable); gl_free(zb->dctable); } #if 0 int ZDither_lookupColor(GLint r,GLint g,GLint b) { GLubyte *ctable=zdither_color_table; return ctable[_MIX(_DITH0(_R, r), _DITH0(_G, g),_DITH0(_B, b))]; } #endif #define DITHER_PIXEL2(a) \ { \ register GLint v, t, r, g, c; \ v = *(GLuint*)(pp + (a)); \ g = (v & 0x07DF07DF) + g_d; \ r = (((v & 0xF800F800) >> 2) + r_d) & 0x70007000; \ t = r | g; \ c = ctable[t & 0xFFFF] | (ctable[t >> 16] << 8); \ *(GLushort*)(dest + (a)) = c; \ } /* NOTE: all the memory access are 16 bit aligned, so if buf or linesize are not multiple of 2, it cannot work efficiently (or hang!) */ void ZB_ditherFrameBuffer(ZBuffer* zb, GLubyte* buf, GLint linesize) { GLint xk, yk, x, y, c1, c2; GLubyte* dest1; GLushort* pp1; GLint r_d, g_d, b_d; GLubyte* ctable = zb->dctable; register GLubyte* dest; register GLushort* pp; assert(((long)buf & 1) == 0 && (linesize & 1) == 0); for (yk = 0; yk < 4; yk++) { for (xk = 0; xk < 4; xk += 2) { #if BYTE_ORDER == BIG_ENDIAN c1 = kernel8[yk * 4 + xk + 1]; c2 = kernel8[yk * 4 + xk]; #else c1 = kernel8[yk * 4 + xk]; c2 = kernel8[yk * 4 + xk + 1]; #endif r_d = ((c1 << 2) & 0xF800) >> 2; g_d = (c1 >> 4) & 0x07C0; b_d = (c1 >> 9) & 0x001F; r_d |= (((c2 << 2) & 0xF800) >> 2) << 16; g_d |= ((c2 >> 4) & 0x07C0) << 16; b_d |= ((c2 >> 9) & 0x001F) << 16; g_d = b_d | g_d; dest1 = buf + (yk * linesize) + xk; // NOTE BY GEK: The following line was modified to fix a compiler warning, // casting zb->pbuf to GLushort* pp1 = (GLushort*)(zb->pbuf) + (yk * zb->xsize) + xk; for (y = yk; y < zb->ysize; y += 4) { dest = dest1; pp = pp1; for (x = xk; x < zb->xsize; x += 16) { DITHER_PIXEL2(0); DITHER_PIXEL2(1 * 4); DITHER_PIXEL2(2 * 4); DITHER_PIXEL2(3 * 4); pp += 16; dest += 16; } dest1 += linesize * 4; pp1 += zb->xsize * 4; } } } } #endif